Well-designed ZNV2O6/G-C3N4 2D/2D nanosheets heterojunction with faster charges separation via pcn as mediator towards enhanced photocatalytic reduction of CO2 to fuels

Fabrication of well-designed 2D/2D heterojunction composite with effective interfacial contact by incorporating zinc vanadium oxide (ZnV2O6) and protonated g-C3N4 (pCN) for enhanced photocatalytic CO2 reduction has been investigated. The 2D/2D ZnV2O6/pCN samples, synthesized by a one-pot solvotherma...

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Bibliographic Details
Main Authors: Bafaqeer, Abdullah, Tahir, Muhammad, Amin, Nor Aishah Saidina
Format: Article
Published: Elsevier B.V. 2019
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Online Access:http://eprints.utm.my/id/eprint/87450/
http://dx.doi.org/10.1016/j.apcatb.2018.09.097
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Summary:Fabrication of well-designed 2D/2D heterojunction composite with effective interfacial contact by incorporating zinc vanadium oxide (ZnV2O6) and protonated g-C3N4 (pCN) for enhanced photocatalytic CO2 reduction has been investigated. The 2D/2D ZnV2O6/pCN samples, synthesized by a one-pot solvothermal method, were analysed using XRD, SEM, EDX-mapping, TEM, N2 sorption, XPS, UV–vis, RAMAN and PL characterization techniques. It was observed that surface charge modification through protonation of graphitic carbon nitride serves as a mediator and trapped photo-excited electrons. The performance of composite catalysts was investigated in a liquid and gas phase photocatalytic systems under UV and visible light irradiations. Using slurry system, CH3OH production rate enhanced up to 3742 μmol g-cat−1 over ZnV2O6/pCN, 1.15 and 5 times higher than the pure ZnV2O6 (3254 μmol g-cat−1) and pCN (753 μmol g-cat−1) samples, respectively. Instead, the CO evolution rate as a main product over ZnV2O6/pCN nanosheets of 3237 μmol g-cat−1 was obtained using gas phase system. This enhanced activity can be mainly ascribed to the addition of pCN with ZnV2O6 in a controlled ratio as well as synergistic effect of ZnV2O6/pCN nanosheet heterojunctions. Besides, hierarchical structure, higher interfacial interaction, abundant 2D coupling interfaces and efficient separation of charges could efficiently promote both the photo-activity and products selectivity. The obtained ZnV2O6/pCN 2D/2D nanosheets heterojunction with a mediator exhibited excellent photocatalytic stability, which prevailed even after 32 h of operation time for continuous CH3OH production. The possible reaction mechanism anticipated to understand the movement of electrons and holes for CO2 reduction over the ZnV2O6/pCN photocatalyst.